1. Field of the Invention
The invention relates to an evaporator, in particular for a motor vehicle air conditioner.
2. Description of the Background Art
Motor vehicle air conditioning systems known from the conventional art usually have a refrigerant circuit in which the refrigerant passes through a condenser, an expansion valve, an evaporator and a compressor. The evaporator is used in the refrigerant circuit to convert the refrigerant, which is metered by the expansion valve situated upstream from the refrigerant circuit and injected in expanded form, from the liquid state to the gas phase. The refrigerant, which has exited the expansion valve and is no longer under pressure, gradually converts to the gaseous state when it passes through the evaporator, for which purpose the heat previously removed in the condenser of the air conditioner is again required in the form of evaporation heat. The required heat is removed from the interior air of the vehicle, which is conducted past a fan, thereby producing cold air which is fed back into the vehicle interior.
By cooling the air flow in the evaporator, the moisture contained in the air flow condenses onto the cool surface of the evaporator, thereby forming water droplets which drip onto the outflow side of the evaporator due to gravity, where they are then collected and removed by a corresponding device, for example a collecting tank.
DE 44 10 120 C2 describes an air conditioner for a motor vehicle, in which the condensation liquid accumulating in the housing of the air conditioner is easily collected and discharged from the air conditioner. For this purpose, a duct is provided in the bottom of the housing of a refrigerant evaporator, this duct running in an area below the evaporator and ending in an opening which is provided at the lowest point below a radiator disposed adjacent to the evaporator.
However, it is important not only to quickly and effectively discharge condensation water from the air conditioner, but also—particularly in commercial vehicles such as tractors and towing vehicles—there is the problem of the overflowing of condensation water which has been collected but not yet discharged from the air conditioner when a vehicle of this type travels at a steep angle uphill or downhill.
Commercial vehicles of this type, such as the aforementioned tractors and towing vehicles, may be subjected to uphill and downhill slopes of up to 25°. To avoid unwanted spillover of the condensation water collected below the evaporator, a housing restriction plate is additionally provided in front of and behind the evaporator of the motor vehicle air conditioner as protection in these types of vehicles. However, particularly in this type of commercial vehicle, a large air flow, which is fed through the evaporator, is required in order to achieve the desired cooling capacity. By providing the housing restriction plate, however, the flow cross section or the evaporator surface subject to the air flow is partially blocked by the restriction plate and thereby reduced in size, which results in an unwanted reduction in the capacity of the motor vehicle air conditioner.